Machines of the type of interest to this invention typically have an elongated boom which is pivotally attached about a horizontal axis on the machine. The machine itself may be capable of several degrees of freedom of movement, and the distal end of the boom is capable of at least pivotal motion about the boom horizontal axis. Such machines may be used for demolition or clearing rubble at a work site, and may be used for other tasks such a assisting in the reclaiming of metals and other materials in junk yards and reclaiming centers. It is common for such activities to utilize bulldozers, backhoes, and front end loading devices for the handling, demolition and removal of rubble and reclaimable materials. Bulldozers are frequently used to push debris and rubble into piles and loaders of various types are then used to transfer the debris and rubble into trucks for removal from the work site. Rubble at a building demolition site may include all types of wood, concrete and steel materials and all of such materials frequently become entangled and interlocked with one another, making the removal task difficult. For example, demolition sites having steel-reinforced concrete materials among the rubble frequently require the use of electrical cutting torches to separate entangled steel members from the rubble to permit loading of trucks for removal from the site. The handling of such materials is not only dangerous but is also costly and time consuming. There has long been a need for a grapple which will permit the separation and loading of such debris and rubble quickly and without the necessity of stopping the machine loading process while debris remnants are cut apart and otherwise untangled.
It is therefore desirable to utilize in such work a grapple having facility for grasping and removing materials, and having an association therewith a cutter for severing entangled materials to permit material handling in moderately sized loads. One such device is shown in my U.S. Pat. No. 4,104,792, issued Aug. 8, 1978, which describes a grapple having an attached shearing mechanism, each of which are independently hydraulically operated to permit both a cutting operation and a grappling operation to be manipulated from the operator's station in a backhoe. The device described in this patent requires separate shearing and grappling operations, but permits them to be accomplished with the same machine. The machine is particularly useful for operations such as the reclaiming and reprocessing of junk automobiles, wherein the shearing mechanism may be used to quickly sever the automobile rim and tire to permit separation thereof.
Heavy duty shears of the type that are powered by hydraulic cylinders are proving more and more useful in handling scrap and especially metal scrap of all sorts. Such scrap comes in many different forms, and may be in the form of pipes made of steel or soft iron or cast iron, ranging in sizes from 2 inches or smaller, and up to 8 or 10 inches in diameter or larger; structural beams such as I-beams, channels, angle beams in a large range of sizes, up to 8 or 10 inches across and larger; rods and heavy cables having diameters of 2 to 3 inches and larger, metal sheets and plates and formed metal of all sorts including wheels and automobile and truck frames, and a myriad of long and short pieces of stock and metal pieces that are cast, rolled, stamped or otherwise formed, both singly and in various types of assembly.
The prior art has included numerous shears such as that illustrated in U.S. Pat. No. 4,198,747; Pat. No. 4,188,721; and Pat. No. 4,104,792. Typically, these heavy duty shears mount on the dipper stick of a backhoe so that the shears may be controlled fairly well in handling various types of scrap and cutting the scrap into smaller pieces or lengths.
However, the prior art shears have had numerous disadvantages, not permitting the shear to be used as efficiently and rapidly as may be desired, considering the amount of scrap that must be reduced in size before further processing.